Overfishing threatens the world’s oceans—but there may be hope
Global efforts may help reverse the tide of overfishing’s harmful impacts on the planet.
Overfishing is the harvesting of wildlife from the sea at rates too high for species to replace themselves. Scientists have been sounding the alarm about this looming catastrophe for decades. But recent efforts by global leaders may offer hope to avoid what could be a catastrophe.
Here’s a look at the critical issues in overfishing—from its effects on biodiversity to continuing challenges.
Overfishing causes
The earliest overfishing occurred in the early 1800s when humans, seeking blubber for lamp oil, decimated the whale population around Stellwegen Bank, off the coast of Cape Cod.
Some fish consumed in the United States, including Atlantic cod, some species of herring, and California’s sardines, were also harvested to the brink of extinction by the mid-1900s.
These isolated, regional depletions were highly disruptive to the food chain—which only became more precarious in the late 20th century.
(Many freshwater fish species have declined by 76 percent in less than 50 years)
National Geographic History Magazine
In the mid-20th century, countries around the world worked to build their fishing capacities to ensure the availability and affordability of sources of protein.
Favorable policies, loans, and subsidies spawned a rapid rise of big industrial fishing operations, which quickly supplanted local fishers in coastal communities as the world’s main source of seafood.
These large, profit-seeking commercial fleets were aggressive, scouring the world’s oceans and developing ever more sophisticated fishing methods and technologies for finding, extracting, and processing their target species.
Millions of people soon grew accustomed to having access to a wide selection of fish at affordable prices.
(These photos show what overfishing looks like)
But by 1989, when about 90 million metric tons of fish were taken from the ocean, the industry had hit its high point, and yields have declined or stagnated ever since.
Fisheries for the most sought-after species, like orange roughy, Chilean sea bass, and bluefin tuna, have collapsed for lack of fish. In 2003, a scientific report estimated that industrial fishing had reduced the number of large ocean fish to just 10 percent of their pre-industrial population.
(Why high seas fishing isn’t just destructive—it’s unprofitable.)
Impacts on biodiversity
Faced with the collapse of large-fish populations, commercial fleets began traveling deeper in the ocean and farther down the marine ecosystem for viable catches.
This so-called “fishing down” has triggered a chain reaction that is upsetting the ancient and delicate balance of the sea’s biologic system.
Coral reefs, for example, are particularly vulnerable to overfishing. Reefs rely on fish to eat algae, keeping the coral clean and the ecosystem in balance so the coral can continue to grow.
(This destructive fishing style doesn’t just harm marine life)
Fishing out too many herbivores—whether intentionally or as bycatch—can weaken reefs and make them more susceptible to being ravaged by extreme weather events and climate change. Fishing gear and debris can also physically destroy the fragile corals that make up the reef foundations.
Overfishing can also harm other marine species. Trawling, a method in which boats pull massive nets behind them in the water, pulls in more than just shrimp and bluefin tuna. It captures just about anything in its path. Sea turtles, dolphins, sea birds, sharks, and other animals have all faced existential threats as bycatch.
(Green lights could save birds and turtles from fishing nets)
Preventing overfishing
Over the years, as fisheries have caught less and less, humans have begun to understand that the oceans, assumed to be unendingly vast and rich, are in fact highly vulnerable.
(The sea is running out of fish, despite nations’ pledges to stop it)
Many scientists say most fish populations could be restored with aggressive fisheries management and better enforcement of laws governing catches, including instituting catch limits. An increased use of aquaculture, the farming of seafood, would also help. And in many regions, there is reason for hope.
The United Nations Food and Agriculture Organization (FAO)—which lays out international standards for fisheries management—said in its 2024 report that the percentage of stocks that are sustainably producing the most food possible—the goal of fisheries management—have increased to the highest levels yet, from 2020 to 2022.
(These ocean threats are changing the planet)
Still, many challenges remain. Global marine animal consumption continued to rise at nearly twice the rate of population growth in 2022 since 1961, and some low-income countries in Africa and Asia are still engaging in unsustainable fishing practices.
“Targeted policies, technology transfer, capacity building and responsible investment are crucial to boost sustainable aquaculture where it is most needed, especially in Africa,” the report said.
Can we stop overfishing?
Government subsidies to the fishing industry remain a significant challenge to reversing this troubling trend. One global survey found that in 2018 nations spent $22 billion on so-called harmful subsidies that fuel overfishing—a 6 percent rise from 2009.
As National Geographic reported at the time, harmful subsidies are those that fund practices that would not otherwise be profitable, such as for industrial trawlers’ fuel costs. China, for example, has increased its harmful subsidies by 105 percent over the past decade.
(Climate change is depleting our essential fisheries)
World Trade Organization members have been discussing how to limit these subsidies since 2001 and members of the United Nations pledged to forge an agreement by 2020.
After arguing in 2021 that failing to reach an agreement “would jeopardize the ocean’s biodiversity and the sustainability of the fish stocks on which so many depend for food and income,” WTO Director-General Ngozi Okonjo-Iweala announced in September of 2025 that WTO members had agreed on a legal framework that prohibits government support of illegal fishing and exploitation of stocks.
(Can Portuguese sardines make a comeback?)
There’s still more to be done, but experts agree that this step will go a long way toward helping to save the world’s oceans from overfishing.
